[PATCH net v4 0/5] net: phy: postpone PHY interrupts during sleep with MAC-managed PM

[Igor Velkov]

> - Whether the issue was actually triggered, or is only theoretical

Patch 5 fixes a hang seen on Helios64 (dwmac-rk, RTL8211F): in s2idle
without WoL the board hung or reset 10 of 10 times without the series.
The PHY IRQ thread stalls its CPU on an MDIO read while the GMAC clocks
are off, so that CPU never answers the NMI:

  watchdog: CPU0: Watchdog detected hard LOCKUP on cpu 1
  After 10 seconds, these CPUS still haven't responded to the NMI: 1

Patches 1-4 fix defects found by code inspection and Sashiko review;
they were not triggered.